最新刊期
卷 46 ， 期 3 ， 2014
- 摘要：Abstract:In order to study whether the high-water rapid-setting material (HRM) have the ability to control the Strata movement chronically and effectively. In this research, transient mechanical tests and microscopic scanning had been performed on HRM. HRM creep experiments in air environment and water environment were conducted through continuously gravitational loading way. At the same time, based on creep experiments, the rheological model and rheological parameters of HRM have been identified. The results of creep experiments and rheological identification showed that the strength of HRM will be reduced in air environment, and water environment is beneficial for its strength reinforcement. The creep behavior stability of RHM is determined by whether its loading level is above or below its yield stress. The creep law of HRM in water environment can be better simulated by the Burgers model.关键词：water environment;high water rapid setting material HRM;creep experiment;creep law;rheological model
- 3221
- |
- 3
- |
- 0
发布时间：2023-11-14 -
Study on Unloading Relaxation Characteristics of Foundation Rock Mass in Middle Ground stress Region
摘要：Abstract:In order to reveal the unloading relaxation characteristics of foundation rock mass after excavation in the middle-ground stress region,supplement the unloading relaxation theory of hydropower projects in western China,and provide scientific basis for the latter engineering treatment measures of Dagangshan hydropower station,the Dagangshan hydropower station was studied. Based on the study of geological background conditions and relying on field investigation and a large number of exploration drillings,geophysical exploration technics,hole camera technique,et al.,the characteristics of foundation rock mass after excavation in the middle-ground stress region were discussed,including the supergene and the endogenous unloading relaxation phenomenon,which assume the fissures opening,rock mass loosening and entirety relaxation, but without any new rock failure.Meanwhile,the unloading relaxation characteristics of foundation rock mass were markedly controlled by the structure of rock mass in the middle ground-stress area.关键词：foundation rock mass;unloading relaxation;middle ground stress area;dagangshan hydropower station;structure of rock mass- 2857
- |
- 3
- |
- 2
发布时间：2023-11-14 - 摘要：Abstract:To investigate the anti-seismic performance and its affecting factors of new type 3D-wall,the failure process,bearing capacity,load-displacement hysteretic curve and load-strain curve of specimens were obtained by the quasi-static test of three new type 3D-walls.The carrying capacity,formability and energy dissipation capacity of the wall were analyzed.Experiment results indicated that new type 3D-wall is of good ductility and energy dissipation capacity. Depth-width ratio and structural measure in the end of the wall are the major influence factors on the anti-seismic performance of the walls.The flexural failure is more likely to observe in the wall with large aspect ratios,which increases the ductility and energy dissipation capacity of structure.Structural measure in the end of the wall can effectively increase stiffness,carrying capacity,ductility and energy dissipation capacity of the wall,but it has a positive effect for delaying the appearance of cracks.关键词：new type 3D wall;low cycle reversed horizontal loading;seismic response
- 2658
- |
- 5
- |
- 1
发布时间：2023-11-14 -
Influence Analysis of Characteristics and Distribution Types of Soil Parameters on Slope Reliability
摘要：Abstract:The characteristics and distribution types of soil parameters have great influence on the reliability of slope stability.However,this problem is not studied sufficiently in the past.In the present paper,the probabilistic methods of the slope reliability were used,and the influence of the limit state equation,variability and distribution types of soil parameters to the slope reliability were studied.The difference between the reliability index calculated by the probabilistic and non-probabilistic reliability method was compared. The results of the probability-based slope stability analysis showed that the simplified Bishop method is more rational than the Sweden slice method.The lognormal distribution function for soil parameter cand student-T distribution function for soil parameter φwere suggested to the situation with rare samples and the distribution function of the soil parameters is difficult to determine.The non-probabilistic reliability analysis method can be used and served as an effective complement to the probabilistic methods.关键词：reliability of slope stability;first order second moment method FOSM;variability;Sweden slice method;simplified Bishop method;student T distribution- 2648
- |
- 3
- |
- 4
发布时间：2023-11-14 - 摘要：Abstract:Water damage phenomenon of spur dike is widespread and influenced by many factors,and the current research results on it is under the condition of constant flow,which can’t be good enough to solve practical problems.Through flume model experiment,under the action of the average daily flow process of natural river,degree of local scour of spur dike was compared respectively with the same return period when maximum flow and flood period as a total annual maximum flood peak discharge and half maximum flood.The results showed that the peak flow plays a leading role in scour depth,the flood volume plays a leading role in scour scope,and effective flood period on the scope and scour depth of the pit are its leading role.Meanwhile,the analysis of the development of scour pit indicated that the range of the scour pit is not increases with time gradually.关键词：unsteady flow;spur dike;local scour;sensitivity factor;scour process
- 3007
- |
- 9
- |
- 5
发布时间：2023-11-14 - 摘要：Abstract:By using depth-averaged two-dimensional hydrodynamic model to simulate water depth and velocity distribution under different flow rates around L-shape and orthogonal shape ecological spur dikes, and drawing characteristic of its flow field,the impact range was acquired on setting spur dikes around Schizothorax Prenanti spawning ground.Based on Schizothorax Prenantisuitability curves, WUA value can be got from repairing river.Research results showed that L-shape and orthogonal shape ecological spur dikes,the ratio of its body length to river width kept between 0.25 and 0.33 and the ratio of its head length to the length stayed between 0.20 and 0.25,staggered in the river,which can create a suitable flow pattern and satisfy the hydraulic characteristics of Schizothorax Prenanti spawning and increase WUA value. After the rehabilitation measures were carried out,the hydraulic condition similarity was high.关键词：Schizothorax prenanti;hydraulic habitat;L shape;orthogonal shape ecological spur dike
- 2828
- |
- 9
- |
- 5
发布时间：2023-11-14 - 摘要：Abstract:Computational precision and error control are very important to the numerical computation of the stochastic finite element method.Based on theory of random fields and perturbation finite element method,computational formulas of expected values and nth-order central probabilistic moments of the random variable were derived.A computational precision control algorithm in perturbation-based stochastic finite element method was proposed,which makes it possible to specify the accuracy of the solution before expected values and variances of structural responses were calculated separately.The 0~Nth order equilibrium equations of the perturbation-based stochastic finite element method were formulated. One dimension linear elastic prismatic bar subjected simple unidirectional tension was studied with this method.The results of this analysis showed that comparing with second-order perturbation approach, the Nth-order method can improve efficiently the accuracy of stochastic perturbation technique.关键词：stochastic finite element method;perturbation technique;random parameters;computational precision
- 2597
- |
- 3
- |
- 0
发布时间：2023-11-14 - 摘要：Abstract:In order to characterize the increase of the sediment discharge caused by the Wenchuan earthquake and post-seismic heavy rainfall in the upper Min River,the SPOT images,aerial photographs and digital elevation map were interpreted,and landslides,mudslides in the area were marked.Data on sediment discharge,rainfall,landslides,and debris flows were collected for the period of 1980—2010 to describe the effects of the Wenchuan earthquake and post-earthquake heavy rainfall on the increase in sediment discharge of the area.The relationship among precipitation,sediment discharge,landslides,and debris flows before and after the Wenchuan earthquake was analyzed.The variation trends of sediment discharge in the river basin before and after the earthquake were calculated quantitatively.The research results showed that sediment discharge increased by approximately 30% due to coseismic uplift,coseismic landslides,and debris flows after the Wenchuan earthquake.The sediment discharge caused by heavy rainfall after the earthquake was 1.75 times larger than that before the earthquake.The percentage contribution of the sediment yield of debris flows induced by heavy rainfall after the earthquake to the increase in sediment discharge was 37.49%.The heavy rainfall zone basically coincided with the earthquake fault zone and the seismic landslide zone.Therefore,there was a positive-feedback relationship between the increase of sediment discharge and heavy rainfall after the Wenchuan earthquake.The loosening of surface materials and landslides driven by the Wenchuan earthquake resulted in an increase in sediment discharge into the river,bringing about a great disaster which will need to be addressed in the coming decades.关键词：Wenchuan earthquake;upper reaches of the Min River;heavy rainfall;increased sediment discharge
- 2745
- |
- 1
- |
- 3
发布时间：2023-11-14 - 摘要：Abstract:For the problem that mobile terminals can hardly show the three-dimensional models fast and realistically,the adaptive mesh refinement architecture adapting to mobile terminals was proposed.The general adaptive refinement template was designed to reduce the number of template and vertex buffer object in the traditional mesh refinement.Then the crack was solved with offsetting the parametric barycentric coordinates after analyzing the crack problems of multi-resolution detail meshes.The edge refinement level was optimized by adjacent surfaces in order to avoid the cut phenomenon of screen space refinement metric.Finally,Phong refinement was introduced in the architecture to smooth curved surfaces.The experimental results showed that this mobile terminal adaptive mesh refinement architecture could effectively improve the 3D graphics rendering efficiency of the mobile terminals in the case of meeting the visual demand.关键词：mobile terminals;adaptive refinement template;multiresolution mesh;eliminating crack;refinement metric
- 2825
- |
- 1
- |
- 0
发布时间：2023-11-14 - 摘要：Abstract:Machine learning methods were presented to identify deceptive reviews.With the integration of knowledge from computational linguistics and psycholinguistics,supervised method was developed to evaluate the performance of different feature modelings,and select the best mixed features.Then,two semi-supervised learning methods were designed to exploit the large amount of unlabeled data.The results showed the proposed methods outperform the current baselines.关键词：machine learning;semi supervised learning;computational linguistics;deceptive reviews
- 3355
- |
- 1
- |
- 4
发布时间：2023-11-14 - 摘要：Abstract:Aiming at the problem of event classification of on-line network information content security incidents,LDA was introduced,which uses the characteristics that network user’s communication information includes time,relationship and content characters.A real-time multi-dimension information association-LDA (RMIA-LDA) model and algorithm were proposed,which uses the communication time character as timeline,and LDA model to calculate the results of classification of communication relationship and communication content characters in each time slice.After the similarity metric calculation of the classification results and merging them with the results of update data,the result of current on-line events classification was obtained.Experimental results showed that the proposed model and algorithm can achieve the goal of on line information content security incidents classification effectively.It has better performance than the existing algorithms.关键词：event classification;information content security incidents ICSI;latent Dirichlet allocation LDA;similarity metric;Gibbs sampling
- 2731
- |
- 7
- |
- 1
发布时间：2023-11-14 - 摘要：Abstract:To compensate the lack of systematicness and realistic model,heterogeneities were classified into several categories,a heterogeneity space model was built up by utilizing space theory,and the variation trend of dynamic heterogeneity was discussed.Then,an energy efficient random key pre-distribution protocol was proposed, which is inspired by dynamic energy heterogeneity.Under a certain heterogeneity space model,several evaluation metrics including long-term network connectivity,resilience and lifetime were also analyzed. Simulation result showed that by rational using of heterogeneity,the proposed protocol doesn’t only keep connectivity and improve resilience,but also provide a much better network lifetime than other protocols.关键词：sensor network;heterogeneity;key predistribution;performance evaluation
- 2734
- |
- 1
- |
- 1
发布时间：2023-11-14 - 摘要：Abstract:The notion of decision discernibility set and definition of attribute reduction based on decision discernibility set were presented.It was proved that attribute reduction acquired from the definition is equivalence to attribute reduction based on positive region.And then, the method of horizontally partitioning decision table was proposed and the sub-decision table can be assigned to different network nodes and finish computing core attribute and attribute reduction based on sub-decision discernibility set.Finally, the example analysis experiment results form datasets of UCI showed that the proposed parallel algorithms are efficient and effective.关键词：rough set;decision discernibility set;core attributes;attribute reduction
- 2832
- |
- 5
- |
- 1
发布时间：2023-11-14 - 摘要：Abstract:In order to solve the problem that two tenants required to fair share equijoin size in management-type SaaS (software as a service),both a combinational formula of equijoin size and a share protocol of encrypted data equijoin size across private database were proposed.The universal set of 2-tuple was sent to the other tenant by service provider,which was constituted by a sharing attribute value and a hash values of others attributes to corresponding tuple.After the sharing attribute value of 2-tuple was re-encrypted,tenant sent them to the other.Both the ciphertext intersection of sharing attribute and the number of each element corresponds to tuples were calculated by tenant independently.By the combinational formula of equijoin size,the equijion size was fairly shared between tenants.The integrity and security showed that the share protocol of equijoin size was perfect and safe in the semi-honest model.By the efficiency analysis,the computation and communication costs were 50% and about 68% of those in utilizing the fair sharing information by Agrawal’sprotocol. It met the basic needs of management-type SaaS by prototype testing.关键词：relational database;encrypted data;equijoin size;sharing protocol;software as a service
- 2419
- |
- 1
- |
- 0
发布时间：2023-11-14 - 摘要：Abstract:The key issue of atmosphere turbulence simulation is how to generate multi-layer turbulence phase screen with high precision. Classical spectral inversion method needs to take up lots of computer resources.In this case, it leads to impossible parallel computing and slow calculation.In order to remedy these drawbacks,a new method was proposed and implemented based on parallel computation and multi-disk memory mapping.The basic idea of the method was that by using multi-disk to temporary storage large files,many data blocks were mapped into memory for parallel computing.The function interfaces provided by operating system were used to implement block automated memory mapping mechanism without human intervention.Experiments showed that both the accuracy of simulation experiment and the speed of generation of turbulence phase screen have greatly ascended.Moreover,the method could not only be used to generate big data turbulence phase screen parallel,but also could be applied to general big data in scientific computation and computer simulation.关键词：computer simulation;atmosphere turbulence;memory mapping;parallel computation
- 2979
- |
- 1
- |
- 1
发布时间：2023-11-14 - 摘要：Abstract:In order to develop a high-performance crawler application for the active measurement of P2P IPTV,based on degree-rank to capture peers’ information，a new algorithm was proposed.Firstly,a similar strategy of breadth-first search (BFS) was adopted to undertake the initial crawling of peers’ information in the overlay.Subsequently,the captured peer list was sorted according to the size of peer’s degree.Finally, the sorted peer list was provided to distributed crawler system as the input so as to start the real-time collection of peers’ information.The experiment results showed that the performance of the proposed distributed crawler system is better than other existing crawler systems.Specifically, the distributed crawler can track a very popular channel with about 7 200 online peers in about 30 seconds. The results can provide a good solution for capturing more accurate snapshots of peers’ information and conducting active measurement study.关键词：P2P technology;degree rank;distributed architecture;crawler system;PPTV system
- 2952
- |
- 1
- |
- 0
发布时间：2023-11-14 - 摘要：Abstract:For estimating the parameter information of target chirp signal within multiple chirp signal and noise,which is the conventional familiar model in signal processing,the stochastic resonance (SR) in over-damped bistable system driven by the multiple signals and noise was investigated.Using the energy aggregation on optimal fractional Fourier transform domain of chirp signals,the distorted output signals were filtered on optimal fractional Fourier transform (FrFT) domain,and a new signal-to-interference ratio (SIR) gain defined in optimal FrFT domain was proposed to describe the system performance,and used to observe the generalized SR phenomenon.The simulation results showed that interfering chirp signals could assist weak noise with particle jump,which is called coordinative SR phenomenon (CSR).Moreover, the detection performance of target chirp signal is improved.关键词：over damped bistable system;chirp signal;fractional Fourier transform;stochastic resonance;signal to interference ratio
- 2881
- |
- 1
- |
- 4
发布时间：2023-11-14 - 摘要：Abstract:The present algorithms of iterative detection for serially concatenated continuous phase modulation,which was defined in physical layer of downlink in DVB-RCS2，had a high computational complexity and poor convergence at low signal-to-noise ratio (SNR).The joint iterative demodulation and decoding algorithm based on chaos theory was proposed. A modified Gaussian wavelet of fast convergence was used to control the dynamic region.Combined with delayed feedback control method,transient chaos was suppressed.It improved the convergence of system in low SNR region effectively and reduced the number of iterations.A large number of matched filters were required to compute a priori information of codeword in iterative decoding.Because of large condition number, effective matched filters had a strong correlation.So truncated small eigenvalues method was used to reduce the number of matched filters,which was more suitable for practical implementation with only four matched filters.Simulation results showed that the proposed methods exhibited a better convergence and lower complexity compared with the traditional algorithm,and suitable for all kinds of CPM schemes.关键词：continuous phase modulation;transient chaos;modified Gaussian wavelet;delayed feedback control;truncated small eigenvalues method;iterative processing
- 2519
- |
- 5
- |
- 0
发布时间：2023-11-14 - 摘要：Abstract:Based on the voltage variations,a new approach called ‘lower threshold value,more criterions’ was proposed to enhance the single-line-to-ground fault detection sensitivity in neutral un-effective gounded system. The zero sequence voltage, fault phase voltage and un-fault phase voltages would change simultaneously when the single-line-to-ground fault happened in the system. The variations of the voltages were in different fixed intervals considering the effect of fault impedance and fault distance. Then the fault detection method based on the several voltage variations was proposed. The algorithm based on many voltage variations avoids being affected by normal operations of system and the small features of fault, and the sensitivity of the fault detection was enhanced by lower threshold. It could be used for the high impedance fault detection. The enhancement of anti-interference and anti-fault-resistance of the algorithm was proved by the large numbers of simulations using PSCAD/EMTDC program. The method is beneficial to the accurate and reliable single-line-to-ground fault detection.关键词：un effectively gounded system;single line to ground fault;high impedance fault;fault detection;more criterions;voltage variation
- 2788
- |
- 5
- |
- 1
发布时间：2023-11-14 - 摘要：Abstract:In order to study the effect of electro-heating impact on powder sintering densification of micro-forming fields activated sintering technology(Micro-FAST), the die with copper powders was heated to 600 ℃ at the preset heating rate of 50 ℃/s under the pressure of 100 MPa,and the holding time was 0,then cooled down to 500 ℃.After that,the die was heated at the same heating rate and cooled again between 500 ℃ and 600 ℃,and repeating for 1 to 5 times, the effect of electro-heating impact of fast heating on the preparation of micro copper gear was studied.It was found that with the increase of electro-heating impact cycle index, the densification of sintered micro copper gears with 1.6 mm pitch diameter and 8 teeth is gradually improved. When the electro-heating impact cycle indexes are 5 times, the relative density of micro copper gear is 98.7%, and the whole preparation time is only 53 seconds. It was shown by micro analyses that the fast preparation process of micro copper gear consists of 4 stages, which are rearrangement of powder particles,powder elastoplastic deformation and crush, surface melting and bonding between particles and disappearance of particle interfaces,electro-heating impact cycle,respectively.关键词：Micro FAST;micro copper gear;electro heating impact;micro zone liquid phase
- 3529
- |
- 1
- |
- 1
发布时间：2023-11-14 - 摘要：Abstract:In order to probe into the machinability of hardened steel, the finish turning of quenched AISIH13 steel was performed with YW2A fine cemented carbide cutters,and OM,Dynamometer (YDC-Ⅲ 89B),tool microscope (XGJ-1),scanning electron microscopy (JSM5800LV), and portable roughness tester (TR100) were used to study the effect laws of cutting speed on chip formation,cutting force, tool wear and surface roughness of parts. The results showed that the chip evolves from continuity strip to C type segment, and the cutting force, flank wear and part surface roughness decrease with the increase of cutting speed.The adhesive,oxidation and diffusion wear are dominated in the rake face,the cutting temperature is the main reason, while the fatigue spalling plays a leading role,the mechanical stress is the dominant effect in the range of trial cutting speed.关键词：finish turning;segmental chip;adhesive wear;fatigue spalling
- 2595
- |
- 1
- |
- 2
发布时间：2023-11-14 - 摘要：Abstract:Based on conventional stabilization,a new stabilization method was proposed to improve these wastes of dredged material and phosphogypsum to ideal fill materials.The dredged material and phosphogypsum were blended at the proper proportion firstly, then a little of cement been was added to stabilize the dredged material-phosphogypsum blend. Under some curing period,through the unconfined strength test, the direct shear test and the penetration test, the suitable blend ratios of two wastes, the strength and penetration properties of stabilization soil were obtained. The test results showed that the fittest blend ratios of two wastes is 1∶3.5~1.2∶1.The unconfined strength of stabilized phosphogypsum-dredged material blend is about 450~900 kPa with only the cement content of 100 kg/m3 , and the permeability coefficient kis about 10-5~10-6 cm/s.关键词：phosphogypsum;dredged sludge;stabilization
- 2472
- |
- 1
- |
- 10
发布时间：2023-11-14 - 摘要：Abstract:In order to reasonably determine the remain fatigue life of existing corroded RC bridges,high-cycle fatigue tests were performed on eight corroded reinforced concrete(RC) beams,and the fatigue behavior of RC beams with corroded main reinforcing steel bars were investigated.The test results indicated that the diagonal cracks of specimens emerged and developed quickly under the alternate loads, finally became the main cracks.Most simulate corrosion RC beams appeared shear fatigue failure near the end. The deflection development and crack distribution of specimens were closely related with failure models. With the increase of cycle numbers,the maximum and minimal stresses of corrosion main reinforcement increased gradually, and the stress amplitudes changed little. The maximum and minimal compressing strain of concrete developed quickly, and the strain amplitudes increased stably. The fatigue life of specimens had more discreteness, and the fatigue life of the corroded RC beams was longer than that of natural corrosion reinforcing steel bars subjected to axial tensile fatigue loads under the similar corrosion and stress conditions.关键词：reinforced concrete beam;reinforcement corrosion;fatigue test;fatigue life;durability
- 2661
- |
- 9
- |
- 3
发布时间：2023-11-14 - 摘要：Abstract:Early concrete temperature field change drastically,and its process of heating and heat conduction performance is closely related to the hydration process. Considering the concrete adiabatic temperature rise equation,thermal parameters and boundary conditions of three aspects, the early concrete thermal parameters optimization and accurate temperature field simulation were researched.On the basis of indoor test,using the Python language to write the program optimization inversion based on genetic algorithm,the thermal field subroutine of ABAQUS was embedded into the genetic algorithm,and the adiabatic temperature rise equation parameters were optimized. Considering the coefficient of thermal conductivity and specific heat change and based on the hydration degree,a subroutine of thermal parameters was developed.The above research results was applied to a project example, and the results showed that the change of thermal parameters has important influence on temperature field distribution of early concrete,the thermal parameters considering hydration degree of condition than that without considering the parameter change of conditions, the internal temperature of the pile caps peak increases 7.28%, the highest surface temperature increased by 14.30%, the temperature difference between inside and outside increases 3.81%,and the scope of the higher temperature difference between inside and outside is bigger.Research can be more accurate in the prediction of structure early stress and cracking.关键词：early age concrete;thermal field;degree of hydration;genetic algorithms;parameter optimization
- 2501
- |
- 1
- |
- 5
发布时间：2023-11-14 - 摘要：Abstract:Mineralization of CO2 using thermal activated natural K-feldspar with industrial solid waste phosphogypsum (PG) was studied. The single factor experiments were carried out to optimize the activation conditions and mineralization conditions, and the process was evaluated under the optimal conditions. The results showed that under the conditions of ore/CaSO4 mass ratio, 0.5; calcination temperature, 1 200 ℃; calcination time, 2 h; mineralization temperature, 100 ℃ and initial pressure of CO2, 4 MPa,K extraction ratio reached 87%, and CO2 mineralization ratio reached 7.7%. The new process is economically feasible.
- 3848
- |
- 5
- |
- 5
发布时间：2023-11-14 - 摘要：Abstract:The temperature fields of the sealing rings of a dry gas seal are the basis for analyzing face distortions.Three-dimensional models of the rotating ring,stationary ring,and clearance gap of type-A dry gas seal with a spiral grooved face were built.A three-dimensional steady-state heat conduction equation for the sealing rings was solved using ANSYS Workbench and the temperature fields of sealing rings were obtained.The results showed that viscous shear heat of the gas film was the main heat source of the dry gas seal system.84% of viscous shear heat was transferred to the rotating ring through the seal end face.Only 9.7% of the heat was transferred to the stationary ring.And the remaining was carried away by the leakage gas. The average temperature of the rotating ring was slightly higher than that of the stationary ring.The temperature of the end face for each seal ring was higher than that of the back of the ring.The temperature of the end face for each ring was not uniform and achieved the highest near the root of a spiral groove.These results provide the basis for the improvement of theory on the research of the face distortions of the rotor and the stator of a dry gas seal,the selection of their materials,and design of their structures.关键词：dry gas seal;temperature field;sealing rings;numerical simulation
- 2838
- |
- 1
- |
- 3
发布时间：2023-11-14 - 摘要：Abstract:A method of rapid and nondestructive determination of cimetidine tablets was established by ultraviolet-visible diffuse reflection spectrum coupled with support vector regression (UV-Vis DRS-SVR).By spectral pretreatment,outlier detection and the optimization of parameter of RBF kernel function g,regularization coefficient C,insensitive loss function p,SVR model was established in range of 220.17~980.80 nm with g= 0.02,C= 20,p=0.03.The determination coefficients (R2) of calibration set and prediction set were 0.978 2 and 0.987 1,respectively. Compared with PLS model,the SVR model had better prediction performance for 5 blind samples and 15 commercial cimetidine tablet samples with a RMSEP of 0.036 0 and 0.044 8,respectively.The results showed that UV-Vis DRS-SVR is feasible to apply for quantitative analysis of active compound in pharmaceutical formulations, being expected to be used for the quality control in the process of production of pharmaceutical formulations.关键词：ultraviolet visible diffuse reflection spectrum;support vector regression;cimetidine tablet
- 2447
- |
- 3
- |
- 3
发布时间：2023-11-14 - 摘要：Abstract:On the issues of that the traditional determination method of clamping force has a large error in calculation and failed to guide the construction design of clamping device effectively, the actual application condition of forging manipulator was analyzed and the difference between the theoretical analysis and the practical application was determined to work out a jaw’s mechanical model based on the forging manipulator’s clamping analysis in workpiece’s allowable downward deflection condition. The jaw clamping force in both vertical and horizontal conditions was analyzed with the mechanical model and the clamping force formula of jaw in any rotation angle was established to work out the jaw’s minimum stable clamping force to the workpiece when the forging manipulator meets the workpiece’s downward deflection condition. With the example of the 300 kN forging manipulator’s structure parameters, the jaw clamping force of clamping device was worked out based on the research results, a virtual prototype of the forging manipulator’s claw beam in ADAMS environment was built, and the motion simulation was processed. The analysis result showed the validity of clamping force calculation theory.关键词：forging manipulator;clamping device;mechanical model;clamping force
- 2428
- |
- 5
- |
- 5
发布时间：2023-11-14 - 摘要：Abstract:Spectral analysis for accurate measurement of dynamic stiffness and damping of water lubricated rubber bearing was used,which can filter out the interfering signals caused by bearing itself and external environment.The water lubricated rubber bearing was shocked twice by two shock excitation in different frequencies in the experiment.Different with previous excitation,the inputs were displacement,and based on that, the outputs vibration force can be measured.Thus,the dynamic characteristics can be calculated through spectral analysis.Finally,the influences of load and velocity on the dynamic characteristics of the water lubricated rubber bearing were studied,the results showed that this method can effectively avoid the issues of uncontrollability exciting force due to the unbalanced radial force resulted from whirling motion, which can supply a theoretical guidance for further experiment.关键词：water lubricated;journal bearings;spectral analysis;dynamic analysis
- 2392
- |
- 5
- |
- 2
发布时间：2023-11-14
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0